Where to Put That Gravid Uterus

It’s classic teaching that in supine patients who are pregnant, the weight of the gravid uterus will compress the descending aorta and inferior vena cava. Respectively, this will increase afterload and decrease preload, with the end result being a reduction in cardiac output and blood pressure. On an average day in a pregnant woman’s life this doesn’t result in too much distress, but, since most of our sickest patients end up supine while we are treating them, it becomes a bigger issue should a gravid patient require resuscitation.

As we’ve all been trained, the answer to this problem is simple, of course – tilt the patient on her side and boom, she’s better. However, like most of what we are taught in the classroom, there’s a lot more nuance to how we should handle these patients in actual practice, so lets review some finer points.

Click image for source.

1 – Does your patient really need to be supine?

This may seem like an obvious question, but too often we let our own comfort come before that of our patients. 95% of them indulge us and tolerate laying on their back, but when you’re treating a 38 wk pregnant woman, you should ask yourself if it is truly necessary for her to stay supine. Most of the time she could be in the left-lateral position and patient care would still go swimmingly.

2 – Is the patient pregnant enough?

Another seemingly obvious issue, but I’ve seen it come up before. The patient has to have a large enough uterus to actually compress the great vessels to warrant these maneuvers. 20 weeks is usually a pretty good guideline, but it’s even easier to just look at the patient and make a judgement call. If their belly looks like it’s squashing the vena cava, then fix it. If the only reason you know the patient is pregnant is because she told you, just let her be.

3 – Left or right side down?

Left. It’s been studied, and left is better. Left to lighten the load.

4 – Pad the pelvis or the spine?

Spine. This has also been studied, and you get better results by placing padding under the lumbar spine as opposed to the hip.

5 – Over-tilt, then correct.

This suggestion is based on a small study, and may not create a huge impact, but it certainly makes sense to me. As you initially position the patient, turn them to their far left side before returning them to your desired angle of tilt. It will probably result in better displacement of the uterus and increased blood flow. Here’s the abstract. Hat-tip to Cliff Reid over at Resus.ME.

6 – How much tilt?

15, 30, 40, and 90 degrees are the usual answers depending on the situation, but there’s a few things to keep in mind when deciding which guideline you’d like to use. First, we overestimate how much tilt we are putting patients in, so what we think is 30 degrees is usually more like 20. Second, and more important than any exact angle, is making sure that the patient can tolerate the position and that we can treat them safely and effectively.
It may seem like you’re doing well by a trauma patient if they’re on a long board at 60 degrees to really minimize vessel compression, but if you’re worsening their spinal injury because they’re not adequately secured, it’s game over. If you can’t effectively manage their airway because of the awkward angle, we may term that a “clean kill,” but I promise you, it’s going to be a messy scene.

Click image for source.

My take on the matter is that you should only give them as much tilt as you can get away with without negatively affecting patient care or well-being. If she can rest comfortably in the left-lateral recumbent position, then great. If you can secure a cooperative trauma patient at 30 degrees safely, go right ahead. If you can do CPR compressions at 15 degrees without sacrificing depth or time on the chest, more power to you. If, however, issues affecting patient care crop up at any time, immediately abandon the tilt and go right back to standard positioning, because there’s a better way…

7 – Use manual displacement.

It’s been shown that pushing or pulling the uterus to the left by hand is just as effective as tilting the entire patient, if not more so. It’s also a lot easier, so in my opinion (which doesn’t exactly match that of the AHA), if you have an extra set of hands around, it should be the first line therapy. Here’s a couple of images to guide you, from the 2010 AHA guidelines.

Two-handed pull. Click image for source.

One-handed push. Click image for source.

They really don’t recommend one maneuver over the other, but if you have a choice, I would think that the two-handed method would be easier and result in more effective displacement. Plus, if you’re in the back of the ambulance, most patient care ends up coming from the patient’s left side anyway.

8 – Really, don’t compromise compressions.

I stated this earlier, but when you’re trying to make these maneuvers happen, it’s probably not worth it if you end up performing anything less than ideal CPR. The AHA guidelines on the matter state that we should strive for 27-30 degrees of tilt with compressions, but their data and reasoning aren’t too strong. Personally, I would rather see a team of providers working together to perform good-quality CPR on a supine patient who is pregnant as opposed to a scene of chaos while they struggle to find and apply positional adjuncts – all the while precious seconds are ticking by without compressions being performed. After you factor in the trouble of interrupting, or at the very least reducing the quality of compressions as the patient slides off whatever you used to prop them up, the argument for tilting loses even more traction.

In conclusion: What would I do?

First, if the patient is capable, let them place themselves on their left side, and all is well in the world.

For the minor trauma patient on a backboard, the standard 15-30 degrees of padding under the board should suffice. All you’re trying to do is increase cardiac output enough that your patient stays comfortable while locked in one position on their back.

But, if 30 degrees isn’t working in the above scenario, or the patient is quite sick and you need them supine, immediately have someone perform a two-handed pull of the uterus to the left side. Later, if you have the time and resources, you can use towels or wedges under the patient’s spine to tilt them 15-30 degrees to the left, while still maintaining manual displacement. I haven’t come across any studies examining the combination, but if the patient is sick and you really want to reduce vessel compression as a source of hypotension, this sounds like the ideal method to me.

If the patient arrests, CPR is always going to be your first, second, and third priority. If you happen to have an extra responder or involved bystander, by all means have them provide manual displacement, but only after compressions have started and you have gained some modicum of control over the situation. If you happen to find yourself on an L&D floor (for some ungodly reason) when this resuscitation is happening, they probably have a dedicated tilt-board or foam wedge lying around from when they perform caesareans. By all means use it, because the staff there will probably hate you if you don’t, but I will still leave you with one theme: compressions! Even the AHA states that manual displacement is at least equivalent, if not superior, to tilting, so why waste time on anything else when you have greater priorities.

As always, leave me any questions, comments, or concerns in the comments, I would love to hear from you.

Most of my information was either straight-from, or already referenced in, the 2010 AHA guidelines or this (http://apps.who.int/rhl/reviews/CD007623.pdf) Cochrane Review on patient position during caesarean section. The right vs. left question is analysis 4.1 on page 27, which boils down to single study from 1978. I managed to find the actual study here (http://tinyurl.com/bsnb4u6), and it seems decent enough by 1978 standards.

The rail idea sounds like a good one, so I think I’ll actually measure the angle next time I’m at work. My guess would be in the 10-15 degree range

Excellent. You even hear it said sometimes that the standard “recovery position” for airway management should be left rather than right, but I’ve never heard any justification for that and always suspected it merely evolved from the desired to have the patient facing the tech in an ambulance. But the maternal version makes good sense at least.